Alcoholism and its complications exact a staggering medical cost in the U.S. The increase in infectious diseases is a result of immunodeficiency, and the presence of autoantibodies supports the possibility that autoimmunity may contribute to the organ and tissue damage. Recently, we and others have shown that alcoholics have 1) chronically and markedly activated T-cells, 2) loss or reduction of several lymphocyte subsets, 3) substantial monocyte activation, and 4) functional changes in vitro. Cellular subsets known to be altered phenotypically in alcoholics include CD8+ T-cells, and CD5+ B-cells, and loss of T-cell response to alloantigen in the presence but not in the absence of autologous monocytes. We believe that the loss of subsets and the influence of activated monocytes on the remaining lymphocyte subsets are responsible for much of the immune dysfunction in these patients. The proposal will characterize the mechanisms of subset loss in alcoholics by 1) evaluation of cell-death related marker expression and extent of apoptosis in the activated cell types known to be lost in alcoholics, 2) measurement of the cytokine balance and relative numbers of activated monocytes, 3) analysis of inhibition of T-cell responses to antigen by the activated monocytes, and 4) investigation of the cytokine balance (TH1/TH2) of the remaining lymphocyte subsets in various stages of alcoholism. These evaluations will be carried out on fresh and cultured peripheral blood lymphocytes and monocytes from alcoholic humans under treatment and compared with normal controls. The effect of ethanol will be directly measured on these same functions by the use of short and long-term cell cultures in the presence of carefully controlled continuous ethanol exposures. The methods of analysis are all well-standardized and currently in use in the investigator's laboratory. These include flow cytometry, modifications of several cell-killing assays, and cell proliferation assays. The goal of these investigations is to improve understanding of the significant immunologic changes in chronic alcoholism that underlie the morbidity and death resulting from the increased infectious diseases and organ damage in these patients. This understanding will lie at the heart of initiative for immunotherapy and other interventions designed to reduce the morbidity and mortality in this disease.